Collapsible foundation core for mattress



FIG. 1 is a perspective view of my design for a collapsible foundationcore for mattress;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is an elevated front view thereof;

FIG. 5 is an elevated back view thereof;

FIG. 6 is an elevated right side view thereof; and,

FIG. 7 is an elevated left side view thereof.

I claim the ornamental design for a collapsible foundation core formattress, as shown and described.